Tobacco manipulating machines



March 29, 1966 F. A. M. LABB' 3,242,921

TOBACCO MANIPULATING MACHINES Filed Oct. 30, 1961 uur Mw/f, 4MM,

A TTORNEK United States Patent O TOBACCO MANIPULATING MACHINES Francis Auguste Maurice Labb, Paris, France, assigner to The Molins Organisation` Limited, London, England, a company of Great Britain Filed Oct. 30, 1961, Ser. No. 148,374 Claims priority, application Great Britain, Nov. 4, 1960,

. 6 Claims. (Cl. `131-21) Patented Mar. 29, 1966 in FIGURE l, the perforations in the conveying band being `omitted for clarity, and

FIGURE 3 shows on an enlarged scale a fragmentary sectional view taken substantially on the line III-III in FIGURE l. w

In the machine illustrated in FIGURE l the lower course of a perforated endless conveyor band 1 runs from right to left as shown in the drawing through the upper portion -of a passage 2, the passage being narrow in the direction perpendicular to the plane of FIGURE l. From the passage 2 the band runs through a channel open to the atmosphere and which is defined by opposed walls 9. Above the lower course of the conveyor band I is a suction chamber 4 with an exhaust pipe 5 which communiof the major problems with this type of machine is to maintain the mass per unit length of the filler uniform since any variations in mass cause undesirable fluctuations in the density of the tobacco tiller in the cigarette rod produced therefrom. One means 4of reducing these density variations is to provide means for detecting variations in the mass of the iiller as it passes a given position on the conveyor and then further along the conveyor to provide trimming means, controlled by the detecting means, for removing varying amounts of surplus tobacco as is necessary to produce a filler having as nearly constant mass as possible. This means `of controlling variations in mass has not been very satisfactory, because it does not produce a perfect result.

It is an object :of the present invention to provide a method and' apparatus for obtaining a continuous filler for use in cigarette rod having a consistently uniform mass per unit length.

Briefly, according to the present invention, a method and apparatus is provided for improving the uniformity of the mass per unit length of the filler as it is conveyed through the tobacco manipulating machine. The method comprises thezsteps of subjecting a controlled length of the continuously moving tiller on the conveyor to a substantially uniform pressure to compact the iiller, detecting variations in the mass vper unit length of the filler and controlling in accordance with said variations the length filler and consequently the time to which the filler is subjected to said compacting pressure. The method is based on the fact that by varying the length of time the filler is subjected to the compacting pressure the density of the filler may be correspondingly varied. The compacted filler is trimmed following the detecting operation either by a trimming device set a fixed distance from the conveyor or by a trimming device which is adjusted in rcsponse to further -sensing means operating on the filler and located beyond the trimming device.

. For a better understanding of the nature of this invenl sectional plan view taken substantially yon the line II-II Cates with pumping means which is not illustrated. A continuous flow of air, inducted by the pumping means is drawn through the lower course of conveyor baud 1 into the suction chamber 4. The current of air drawn through the portion of the conveyor band 1 in the upper portion of passage 2 flows upwardly through passage 2 carrying with it cut tobacco which is deposited on the under side of the moving conveyor band I where it is held suctionally. The tobacco filler as it builds up is carried by the l conveyor band 1 out of passage 2 into the channel where the tobacco is confined laterally by the walls 9. An amount of cut tobacco in excess of that required for the cigarette rod is built up on the conveyor band before it leaves passage 2. In the channel the tobacco continues to be held suctionally by air drawn from the atmosphere through the conveyor band I into the suction chamber 4.

Further along the channel a trimming device 6 is provided Which removes surplus tobacco from theviller. The trimming device 6 comprises two co-operating trimming discs only one `of which is shown in FIGURE l. It is in a xed position relative to the conveyor band 1 so that the filler will be trimmed to a constant cross-sectional area, ie., the area delineated by discs of the trimming device, the walls 9 and the band l. The mass per unit length of the trimmed filler will depend on the density or compactness of the filler before trimming and any variations in the density of the built-up filler before the trimming operation will result in corresponding variations in the mass per unit length of the filler after trimming ultimately resulting in a cigarette rod in which the density of the tobacco filler will vary along its length. After passing the trimming device the ller is transferred from the conveyor band 1 `onto a continously moving paper web 3 which is folded over the trimmed filler to form the continuous paper wrapper on the cigarette rod. The above detailed description is of a conventional tobacco manipulating machine such as is described in United States Patent No. 3,030,965 issued to Francis A. M. Labb April 24,1962, and forms no part of the present invention. The following is a detailed description of the improvement in the above described machine which avoids or at least reduces variations in the mass per unit length of the trimmed filler.

Air ilow passing through the ller into chamber 4 is restricted to some extentV by a slotted plate 13 located immediately above the conveyor band I. The plate 13 contains both large slots 17 and 17A and narrow slots 14. The large slots 17A are inside the filler forming part of the machine `and over the passage 2 and the narrow slots 14 and large slots 17 are down stream from slots 17A. When the built-up tobacco filler moves to the left as viewed in FIGURE 1 away from the coniines of the passage 2, it is open to atmosphere. The pressure of the air passing through the tobacco filler and the slots 14 falls from atmospheric pressure to the pressure present in the suction chamber 4. The proportion of this over-all pressure drop which is produced by the slots 14 will depend on the size of these slots. As the remainder -o this over-all pressure drop is produced across the tobacco filler the pressure drop across the ller will also depend on the size of slots 14. Superimposed over the portion of slotted plate 13 containing narrow slots 14 and the irst adjoining large slot 17 is a sliding plate `15 havingk a single long slot 16 which is of the same width as the slots 14. The movement of theY sliding plate 15' lengthwise along slotted plate 13 is mechanically controlled through a rack 1S on one side of the sliding plate which is engaged by pinion 19 mounted -on shaft 22. Rotation of the pinion will cause the sliding plate 15 to move along the slotted plate 13 permitting the long narrow slot 16 in the sliding pla-te 15 to cover varying proportions of large slot 17 immediately below i-t.

Above the conveyor band 1 and downstream from the sliding plate 15 is provided a sensing chamber 19 which has an opening 11 in communication with the conveyorband, the length of the opening 11 being less than a cigarette length. A pipe 12 extends from chamber 10 intol the exhaust pipe 5 so that air is drawn through the filler, the conveyor band and the chamber in the same manner as air is drawn through-the conveyor band elsewhere. Variations from point to point along the length of the filler in the air permeability of the filler which are an indication of variations in density of the filler from point to point along its length, cause corresponding variations in the air pressure drop. There will be a greater flow of air lthrough a length of filler which is less dense than through a length ofhller which is more dense, and thus there will be a higher pressure in chamber 10 in the iirst case than in the second case. The sensing chamber 1i) is connected by a small diameter pipe 20 to a bellows device 21 so that the bellows may move in and out in accordance with changes in the pressure in the sensing chamber 10, and this movement is utilized through the use of a suitable amplifying device such as an electro-mechanical device of known construction to cause shaft 22. and pinion 19 to rotate thus moving sliding pla-te 15.

It will be readily observed that between the left-hand edge of sliding plate 15 and the sensing chamber 1.0' the tobacco ller will be subjected to a substantially uniform pressure drop which is greater than the pressure drop across the tobacco filler when it was passing the narrower slots 14, as a smaller pressure drop will occur across the slots 17 than across the slots 14. By varying the length of and correspondingly the length of time the tobacco liller is subjected to the greater pressure drop in response to fluctuations in the density of the iiller as detected by the sensing chamber 10 the filler becomes compacted land will be more uniform in density than it was when the tiller was positioned on the portion of the conveyor leng-th beneath slots 14. If the sliding plate 15 moves to the left as viewed in FIGURES l and 2 there will. be a greater length of tobacco filler subjected to the air how 'through the narrow slots 14 and 16 and a shorter length of the tobacco iiller subjected to the air llow through the wider slots 17. ln this way a very delicate adjustment is provided to the aforesaid given length of tobacco ller over which the maximum air pressure is employed. Adjustments in pressure vdrop caused by movement of sliding plate 15 are nominal cornpared with the over-all pressure drop along the full length of the conveyor band thus the over-all pressure drop d remains substantially const-ant, irrespective of these minute adjustments.

The tobacco ller normally travels at a uniform speed and, therefore, by adjusting the length of tobacco liller which is subjected to the greater pressure drop under wider slots 17 the length of time to which the continu-ously moving filler is subjected to this compacting pressure is varied thereby making it possible to produce a tobacco ller having very little, if any, variation in density before the ller is subjected to the trimming operation, and an improved cigarette rod is thus produced having a substantially constant den-si-ty along its length.

What I claim as my invention and desire to secure by Letters Patent is:

1. In the manufacture of cigarettes on a continuous rod cigarette-making machine, a method of forming a continuous trimmed tobacco filler which comprises the steps of forming an elongated continuous tobacco ller having at all points along itsv lengthy an excessv of tobacco over that required in the continuous cigarette rod, trimming the filler to remove the surplus tobacco whilst conveying the liller in the. direction of its. length, applying a substantially constant cornpactingv pressure tothe ller, at least before it is trimmed to-increase the density of the filler during the trimming ope-ration, detecting variations in the density of thev ller, andvarying in. accordance with saidvariations in density the period of time during which said compacting pressure. is applied.,

2. A continuousV rod cigarette-making machine cornprising means to form an elongated continuous tobacco filler having at all points along its length a surplus-of tobacco over that required in the cigarette rod,a conveyor to convey the filler lengthwise, a trimming device' to remove they surplus tobacco, a sensing device to detect variations in the density of the ller, means tov apply a substantially constant compacting pressure to a.` length of the filler at least before it is trimmed,v to increase the. density of the filler at .the trimming device, and means responsive to the. variations sensed by said detecting device to vary the length of the filler to which the compacting pressure is applied.

3. A machine as claimed in claim 2v wherein. the sensing device is situated to immediately precede the trimming device to detect variations in the density of the ller after the compacting pressure. has. been applied to` the filler.

4. A machine as claimed inclaim 2 whereinv the conveyor is air pervious, and further comprising; axsuction chamber to draw air through the ller andthe conveyorto hold the ller to the conveyor, and wherein the means toV apply the said compacting pressure tothe filler comprises means to increase the air iiow through saidlength. of the filler tovary the pressure applied to. said length of the iller compared with the airiiow through the fill'erat least immediately upstream of said length.

5. A machine as claimed' in claim 4 and comprising ak rst air-permeable plate between-the conveyor and theA suction chamber, the rst plate having a first area having' a iirst value of air permeability along7 said length of the filler, and having a second area having a second and lower value of air permeability at leastfimmediatelfy preceding said length of the filler, wherebyy the air owthrough. said length of the filler is. increased', andwherein the; means to vary said length of the filler comprises a secondV plate having the same air permeability as the lower valuev of air permeability of the ixeclr plate, means mounting said second plate lagainst the first plate for sliding movement relative thereto, and. between a position in which the second plate overlapsthe rst area of the first plate', and a position in which the second plate overlaps thev second area of .the first plate, and means operable by said sensing device to vary the position of the second plate between said two positions.

6. A machine as claimed in claim 4 and comprising a iirst plate between the conveyor and the suction chamber, the first plate having means defining a first `set of apertures immediately preceding said length of the filler in the direction of travel 'of the filler, `and means defining a second set of apertures larger than the apertures of said first set along said length of the filler to increase the air ow through said length of the filler, and wherein the means to vary said length of the filler comprises a second plate mounted against the first plate for sliding movement relative thereto and having means defining an aperture of the same size as the apertures of said first set, and means operable by said sensing device to move the second plate in the direction of t'ne lengthwise dimension of the filler to vary the amount of overlap between the aperture in the second plate and the first and second sets of apertures in the first plate.

SAMUEL References Cited by the Examiner UNlTED STATES PATENTS 6/1918 Saunders 19-50 12/1934 Rundell 131-110 11/1953 Rault 131-84 7/1958 Lewis et al. 131-84 5/1960 Lanore 131-84 6/1962 Schubert 131-84 9/1962 Levadi 131-21 FOREIGN PATENTS 12/ 1956 Great Britain.

KOKEN, Primary Examiner.

IOSEPH S. REICH, Assistant Examiner. 

2. A CONTINUOUS ROD CIGARETTER-MAKING MACHINE COMPRISING MEANS TO FORM AN ELONGATED CONTINUOUS TOBACCO FILLER HAVING AT ALL POINTS ALONG ITS LENGTH A SURPLUS OF TOBACCO OVER THAT REQUIRED IN THE CIGARETTE ROD, A CONVEYOR TO CONVEY THE FILLER LENGTHWISE, A TRIMMING DEVICE TO REMOVE THE SURPLUS TOBACCO, A SENSING DEVICE TO DETECT VARIATIONS IN THE DENSITY OF THE FILLER, MEANS TO APPLY A SUBSTANTIALLY CONSTANT COMPACTING PRESSURE TO A LENGTH OF THE FILLER AT LEAST BEFORE IT IS TRIMMED, TO INCREASE THE DENSITY OF THE FILLER AT THE TRIMMING DEVICE, AND MEANS RESPONSIVE TO THE VARIATIONS SENSED BY SAID DETECTING DEVICE TO VARY THE LENGTH OF THE FILLER TO WHICH THE COMPACTING PRESSURE IS APPLIED. 